Earlier this year, the star was asked to emcee an event for America's Democratic National Committee in honor of Obama.

He was given a pre-prepared speech to deliver, but Harris admits he was petrified about speaking to a room full of such powerful people, so he turned to his TV writing team to help turn the mundane script into something fun to ease his nerves.

He explains, "What are you supposed to say as your opening remarks for a big giant fundraiser? I'd never done it before. So, I asked if they had prepared a script and so they send over a very stumpy sort of script of things he (Obama)'s done over the year, to sort of rally the crowd. And that kind of freaked me out.

"So I sort of had the How I Met Your Mother scribes take a pass at it... (to add) some jokey bits..."

But Harris still made quite an impression on the President.

He continues, "So I do my opening remarks and then Dave (his partner, David Burtka) and I get ushered back and around (the stage)... because I still have more show to do. And then boom, you turn around the curtain and there's the freakin' President of the United States! And you quickly panic because, like, what do you say? Do you just say, 'It's such an honor. Nice to meet you sir.' Or do you say something familial? I didn't know.

"So I jokingly, (improvised). He turns and goes, 'Oh, hi Neil.' And I jokingly said, 'If you don't mind Sir, I'm kind of in the middle of something.'"

But the actor insists the humor was in good fun: "He (Obama) was actually super incredibly nice and a great man."